Conventionally, there are proposed many pneumatic tires having a tread surface which is provided with a directional tread pattern the tire rotational direction of which is specified in one direction. In the pneumatic tires having such a directional tread pattern, there are pneumatic tires including a tread surface having circumferential grooves disposed on both sides of a centerline of the tire, and lateral grooves extending outward in a widthwise direction of the tire from the circumferential grooves so as to incline towards the tire reverse rotation direction to thereby define rhomboid-shaped or parallelogram-shaped blocks having obtuse-angled corner portions and acute-angled corner portions in its center region (for example, see Unexamined Japanese Patent Application Publication No. 11-91313).
In recent years, circuit courses are opened up to general car users, and the users often have chances to make their cars run a circuit course. When running such a circuit course, a lateral acceleration acting during turning is much greater, compared with that in normal driving when running a public road, and irregular wear different from that in the normal driving is, therefore, created.
In the pneumatic tires having the above-mentioned directional pattern of blocks, there is a problem of occurrence of irregular wear such that the obtuse-angled corner portions of the blocks facing to the circumferential grooves, that is, the obtuse-angled corner portions located on the kicking-out sides of the blocks wear more slowly than other parts thereof.